Years ago, the car developed an intermittant loss of spark. Sometimes the car would stall when it was rolling, and might or might-not start up again. More often I'd park the car and the next time I tried to start it, hot or cold, it wouldn't. Wait a while and maybe it would start again. Maybe.
I tried all kinds of things, and one of them was replacing the Amplifier. Jaguar wanted around $250 for it, but on the Jag-Lovers Forum I found the parts interchange directory, and found out I could open up the Amplfier box and swap out the module inside, which was a $25 part.
I got another Amplifier from a junkyard car and opened it up to verify. They were right. I bought a new module, swapped it out, and put it in my car. Didn't fix the car, but I didn't do any harm, either.
Later on Jaguar Forums, someone had a problem with the amplifier wiring going to the coil, and I had a reason to dig it out and photograph it. So if you're curious what the inside of the Amplifier looks like, here it is.
Click on images to see larger sizes.
The gray module in the middle with the SELECT sticker on it is the GM ignition module. You unplug it, take out the two nuts, and it lifts right out.
The two blade connectors on the side go to the distributor pick-up. The two wires that go directly from the module and through the outer case go to the ignition coil.